Tips for designing crane-supporting structures
o1. Obtain the crane loads; maximum wheel load, lateral loads, and the longitudinal loads from the crane manufacturer’s. Also get the maximum allowable lateral drift in building in inches or millimeters; this is important for industrial buildings with cranes as it takes precedence over the other drift limits established based on height over something; like height over 400 or 500
o2. Calculate the lateral loads, wind, and seismic; for industrial buildings there will usually be large openings in the form of overhead doors, you have to pay attention to that. Most likely the door will be open during a storm, so you have to consider internal wind pressure-this is critical as it will increase the pressure on the walls, and accordingly the drift will be larger. Also the uplift on the roof will be significant. This can be calculated according to ASCE or the Canadian code NBCC-Structural commentaries to part 4 of the code; the Canadian code is a lot easier to interpret and apply, the ASCE is very detailed and involved-they recently changed it to make it easy to apply
o3. For the crane vertical loads do not forget to use impact factor as per the referenced code
o4. Calculate the primary loads and combine them as per the applicable code; do not forget to add the crane loads to the load combinations; the Canadian design guide provides load combination with crane loads
o5. You will have to have two sets of loads combination, ultimate loads (factored loads) for the strength calculations and for selecting the member sizes, and service loads (without load factors) for the lateral drift calculations
o6. Model the structure using a computer program, like Staadpro, and check the resulting lateral drift. The building drift has to be within the limits set by the manufacturer’s; if needed increase column size
o7. Do not forget to apply the crane loads in the longitudinal direction of the building as eccentric loads to the frame columns; these loads cause torsional stresses in the columns
o8. In modeling the building, assume the base of the columns to be hinged, this is conservative as it will give the maximum drift. Do not attempt to fixed the bases as it is not in your hand-that requires tight field
supervision and with concrete cracking you can not have that fixity
o9. For building frames with cranes, use continuous horizontal lateral bracing in the roof, this will help in maintaining the uniformity of the lateral drift of the building- this is important to prevent malfunctioning of the crane
o10. Use moment frames in the lateral direction-the short direction of the structure, as it will not interfere with the crane operation. Provide vertical lateral bracing in the longitudinal direction. There are recommendations for the positioning of the vertical bracing in buildings with cranes, you can check the CISC design guide called crane supporting structures, it is a free download. They have solved examples; you can take a look at
o11. There are special design checks for the knee connection between the rafter and the column it is in the AISC design guide, I can not remember the name of the guide-see if you can google it. I am assuming that you are designing the connection between the column and the rafter, better to leave it to the fabricator, but remember to check for it
o12. Use pretension bolts for bolt connection; refer to the design guides above- these are requirements in both the CISC S16-09 and the AISC to avoid bolts becoming loose due to vibration. There is a check list in the Canadian design guide, you can take a look at
o13. For the crane-runway beam there are special weld recommendations, pay attention to them-they are mentioned in the design guide by James Fisher
o14. For the crane runway beam, use simple spans, do not attempt to fix them as it will create problems
o15. There are special checks for the local flange bending as outlined in the CMAA 74 and 76-CMAA stands for Crane Manufactures of North America- google it and you will get something
Most of this info can be found in the design guide I mentioned above, and also in the AISC design guide #7 called industrial building by James Fisher. My advice to you is to educate yourself about this as there are lots of things that need to be taken care of to avoid crane problems. Use the references I quoted and seek advice from senior members, hopefully you are in the commercial sector as help will always be there
Good luck
o1. Obtain the crane loads; maximum wheel load, lateral loads, and the longitudinal loads from the crane manufacturer’s. Also get the maximum allowable lateral drift in building in inches or millimeters; this is important for industrial buildings with cranes as it takes precedence over the other drift limits established based on height over something; like height over 400 or 500
o2. Calculate the lateral loads, wind, and seismic; for industrial buildings there will usually be large openings in the form of overhead doors, you have to pay attention to that. Most likely the door will be open during a storm, so you have to consider internal wind pressure-this is critical as it will increase the pressure on the walls, and accordingly the drift will be larger. Also the uplift on the roof will be significant. This can be calculated according to ASCE or the Canadian code NBCC-Structural commentaries to part 4 of the code; the Canadian code is a lot easier to interpret and apply, the ASCE is very detailed and involved-they recently changed it to make it easy to apply
o3. For the crane vertical loads do not forget to use impact factor as per the referenced code
o4. Calculate the primary loads and combine them as per the applicable code; do not forget to add the crane loads to the load combinations; the Canadian design guide provides load combination with crane loads
o5. You will have to have two sets of loads combination, ultimate loads (factored loads) for the strength calculations and for selecting the member sizes, and service loads (without load factors) for the lateral drift calculations
o6. Model the structure using a computer program, like Staadpro, and check the resulting lateral drift. The building drift has to be within the limits set by the manufacturer’s; if needed increase column size
o7. Do not forget to apply the crane loads in the longitudinal direction of the building as eccentric loads to the frame columns; these loads cause torsional stresses in the columns
o8. In modeling the building, assume the base of the columns to be hinged, this is conservative as it will give the maximum drift. Do not attempt to fixed the bases as it is not in your hand-that requires tight field
supervision and with concrete cracking you can not have that fixity
o9. For building frames with cranes, use continuous horizontal lateral bracing in the roof, this will help in maintaining the uniformity of the lateral drift of the building- this is important to prevent malfunctioning of the crane
o10. Use moment frames in the lateral direction-the short direction of the structure, as it will not interfere with the crane operation. Provide vertical lateral bracing in the longitudinal direction. There are recommendations for the positioning of the vertical bracing in buildings with cranes, you can check the CISC design guide called crane supporting structures, it is a free download. They have solved examples; you can take a look at
o11. There are special design checks for the knee connection between the rafter and the column it is in the AISC design guide, I can not remember the name of the guide-see if you can google it. I am assuming that you are designing the connection between the column and the rafter, better to leave it to the fabricator, but remember to check for it
o12. Use pretension bolts for bolt connection; refer to the design guides above- these are requirements in both the CISC S16-09 and the AISC to avoid bolts becoming loose due to vibration. There is a check list in the Canadian design guide, you can take a look at
o13. For the crane-runway beam there are special weld recommendations, pay attention to them-they are mentioned in the design guide by James Fisher
o14. For the crane runway beam, use simple spans, do not attempt to fix them as it will create problems
o15. There are special checks for the local flange bending as outlined in the CMAA 74 and 76-CMAA stands for Crane Manufactures of North America- google it and you will get something
Most of this info can be found in the design guide I mentioned above, and also in the AISC design guide #7 called industrial building by James Fisher. My advice to you is to educate yourself about this as there are lots of things that need to be taken care of to avoid crane problems. Use the references I quoted and seek advice from senior members, hopefully you are in the commercial sector as help will always be there
Good luck